In seats for vehicles, there are many features having parts of which plural positions can be adjusted (for example, front-back direction slide of entire seat, up-and-down motion of seating face height, or reclining of seatback (backrest) can be adjusted) in accordance with body type or position of a passenger. The adjustments of these movable parts have been manually performed, but electrical seats, which are adjusted by motor drive, are provided as more useful seats.
In order to drive plural movable parts independently, an electrical seat is thought of as having a structure in which one motor is connected to each output shaft connected to the movable parts. However, the number of motors is increased. Therefore, it is efficient to drive plural output shafts by one motor. In order to realize this, it is known that motor power is transmitted to each output shaft, which is connected to plural movable parts, via a clutch, and the clutch is connected or disconnected and each movable part is selectively driven (see Patent Documents 1 to 4).
Patent Document 1 is Japanese Unexamined Patent Application Publication No. S58-97528. Patent Document 2 is Japanese Unexamined Patent Application Publication No. H6-87363. Patent Document 3 is Japanese Unexamined Patent Application Publication No. S62-183504. Patent Document 4 is Japanese Unexamined Patent Application Publication No. H6-156123.